A nice fiddle back waist is always a pleasure to look at, and when they are as built-up and well-made as this here by Japanese bespoke shoemaker Main d’Or, they are pure eye candy. Just as aesthetically pleasing as the model it’s based on.
The name “fiddle back waist” derives, obviously, from the way it’s highly reminiscent of the back of a violin, which traditionally has the same type of raised ridge along the back, and raised the most along what is also called the waist of the violin. Google “violin back” and you’ll see how alike a waist of the back of a fiddle is to a fiddle back waist of a shoe.
For much more on Main d’Or / Eiji Murata, see here.